Search Publications
Globular cluster systems of relic galaxies
Chies-Santos, Ana L.; Beasley, Michael A.; Leaman, Ryan +6 more
We analyse the globular cluster (GC) systems of a sample of 15 massive, compact early-type galaxies (ETGs), 13 of which have already been identified as good relic galaxy candidates on the basis of their compact morphologies, old stellar populations and stellar kinematics. These relic galaxy candidates are likely the nearby counterparts of high-red…
Molecular gas along the old radio jets of the cluster-central type 2 quasar IRAS 09104+4109
Babul, Arif; Phadke, Kedar A.; Chapman, Scott +4 more
We present Northern Extended Millimeter Array (NOEMA) CO(2-1) maps of the z = 0.4418 cluster-central quasi-stellar object (QSO) IRAS 09104+4109, which trace ~4.5 × 1010 M⊙ of molecular gas in and around the galaxy. As in many low-redshift cool-core clusters, the molecular gas is located in a series of clumps extending along t…
Binary-driven stellar rotation evolution at the main-sequence turn-off in star clusters
Albrow, Michael D.; Deng, Licai; de Grijs, Richard +1 more
The impact of stellar rotation on the morphology of star cluster colour-magnitude diagrams is widely acknowledged. However, the physics driving the distribution of the equatorial rotation velocities of main-sequence turn-off stars is as yet poorly understood. Using Gaia Data Release 2 photometry and new Southern African Large Telescope medium-reso…
Reconstructing three-dimensional densities from two-dimensional observations of molecular gas
Gutermuth, Robert A.; Pokhrel, Riwaj; Federrath, Christoph +2 more
Star formation has long been known to be an inefficient process, in the sense that only a small fraction ϵff of the mass of any given gas cloud is converted to stars per cloud free-fall time. However, developing a successful theory of star formation will require measurements of both the mean value of ϵff and its scatter from …
On the origin of the Kreutz family of sungrazing comets
Lemos, Pablo; Fernández, Julio A.; Gallardo, Tabaré
We evaluate numerically three different models for the parent comet of the Kreutz family of sungrazers: (i) A Centaur on a highly inclined or retrograde orbit that diffuse to the inner planetary region where it became a sungrazer (Model 1). (ii) A parent comet injected from the Oort cloud straight into a near-parabolic, sungrazing orbit. Near peri…
Kinematics of the Milky Way from the Gaia EDR3 red giants and subgiants
Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B. +2 more
We present the results of the kinematic investigations carried out with the use of spatial velocities of red giants and subgiants contained in the Gaia EDR3 catalogue. The 12 kinematic parameters of the Ogorodnikov-Milne model have been derived for stellar systems with radii of 0.5 and 1.0 kpc, located along the direction of the Galactic Centre-th…
Dust in the central parsecs of unobscured AGN: more challenges to the torus
Nadolny, Jakub; Prieto, M. Almudena; Fernández-Ontiveros, Juan A. +1 more
A parsec-scale dusty torus is thought to be the cause of active galactic nuclei (AGN) dichotomy in the 1/2 types, narrow/broad emission lines. In a previous work, on the basis of parsec-scale resolution infrared/optical dust maps, it was found that dust filaments, few parsecs wide and several hundred parsecs long, were ubiquitous features crossing…
The nature of sub-millimetre galaxies I: a comparison of AGN and star-forming galaxy SED fits
Wang, L.; Heywood, I.; Metcalfe, N. +3 more
High-redshift sub-millimetre galaxies (SMGs) are usually assumed to be powered by star formation. However, it has been clear for some time that >20 per cent of such sourcesbrighter than ≈3 mJy host quasars. Here, we analyse a complete sample of 12 sub-mm LABOCA/ALMA 870-µm sources in the centre of the William Herschel Deep Field (WHDF) wi…
The spatially offset quasar E1821+643: new evidence for gravitational recoil
Jadhav, Yashashree; Robinson, Andrew; Almeyda, Triana +2 more
A galaxy merger is expected to cause the formation of a supermassive black hole (SMBH) binary, which itself eventually coalesces through the anisotropic emission of gravitational waves. This may result in the merged SMBH receiving a recoil kick velocity ~100-1000 kms-1, causing it to oscillate in the gravitational potential of the host …
Nitrogen X-ray absorption in the local ISM
García, Javier A.; Gatuzz, Efrain; Kallman, Timothy R.
Nitrogen is one of the most abundant metals in the interstellar medium (ISM), and thus it constitutes an excellent test to study a variety of astrophysical environments, ranging from nova to active galactic nuclei. We present a detailed analysis of the gaseous component of the N K-edge using high-resolution XMM-Newton spectra of 12 Galactic and 40…